How can I animate the transparency of a image texture ontop of another image texture
You can multiply the &quot;top&quot; texture's Alpha by a value between 0 and 1 before feeding it into the Mix node's Fac. Use a Math node (Add &gt; Converter &gt; Math) to multiply. 0 will let the &quot;bottom&quot; texture through; 1 lets through the &quot;top&quot;.